As an apparatus of this type, for example, a camera-integrated video camera is known. Such apparatus uses a magnetic tape as a recording medium, and adopts a helical scan mechanism using a rotary drum in order to increase the recording density on that recording medium.
However, this mechanism produces noise called head rattle when the magnetic tape and rotary recording head come into contact with each other and separate from each other. Since energization to coils of a magnetic motor is switched to drive the rotary drum, its electromagnetic noise is also produced.
Such noise components mix in a built-in microphone, and are recorded together with an audio signal to be originally recorded, causing noisy audio output. To solve such problem, a noise reduction technique for checking a noise spectrum mixing in the microphone in advance, and subtracting components in that frequency band in correspondence with the noise level is known (e.g., Japanese Patent Laid-Open No. 7-177596).
According to this proposal, means for extracting noise spectrum components is provided and control is made to measure the noise level while cutting off an audio signal to be originally recorded, and to make the audio signal have the same level as that of mixing noise, thus reducing the noise by the level of the spectrum, and eliminating the influence on an audio signal when the audio signal is input.
However, with such conventional method, noise components must be checked in advance, and means for extracting noise, e.g., bandpass filters must be prepared as many as the number of noise spectrum components. As an alternative measure, frequencies of closer spectrum components are extracted together, thus reducing the number of bandpass filters. For example, if there are two noise spectrum frequencies, i.e., 1 kHz and 2 kHz, when the center frequency is set at 1.5 kHz and the frequency bandwidth is set to 1 kHz, 1 kHz and 2 kHz of noise components can be extracted. However, in this case, if 1 kHz and 2 kHz have different levels, the average value of these two levels must be calculated or one level must be adjusted to the other. Hence, a subtractive signal of the same level as those of noise components cannot be obtained, and the removal effect is reduced. Furthermore, when an audio signal to be recorded includes a 1.5 kHz component, that component is also attenuated, thus influencing the sound quality. When the level changes due to a change over time, the level to cancel must be re-adjusted. On the other hand, when noise spectrum components change, it becomes difficult to respond to such changes.